I have a 2000 F-250 CC SB 4x4 7.3L PSD. Last night I put my truck in the garage while in 4 wheel drive. Before shutting the truck off, I turned the 4x4 off. This morning while driving to work in the snow, I turned the 4 wheel drive on, but nothing happened. I left the **** in the 4x4 position for about 5 minutes, hoping it would engage but nothing happened. Does anyone have any ideas. I am wondering if it might be a fuse or something? Any ideas are appreciated. Also, does the 100K warranty cover 4x4 issues? Thanks

 

I think it's just confused...

Seriously, I think if you turn the switch to OFF, kill the engine, and let it set for a minute or two it will start working again. I can't explain why (but neither can FORD), but the whole system has to "reset" sometimes.
After it has set for a little while, crank the engine and let it idle for a couple of minutes. Then depress the brake pedal, push in the clutch (if you have a manual tranny) and shift the transmission into neutral. Then just switch the dial to 4WD high and let it stay there for at least two minutes before switching to 4WD Low. (If you need the low range).

Just curious - did you try it after you parked the truck? If so, did you hear the servo motor trying to shift? I know with the PSD it may be impossible.
If you got the bumper to bumper Premium - yes, it will.

 

I did try to engage it after I got to work and parked the truck, but I could not hear anything trying to engage with the PSD idleing.

 

Have you got time to try it this morning? It shouldn't take but 5 minutes after you get it cranked.

Get back to us....

 

I just got back in from trying it. I started the truck, put it in neutral and turned the 4x4 **** to 4 high. I waited about 5 minutes and nothing happened

 

Did you depress the brake pedal? I know it sounds silly, but if you ever do get these things back in the habit....

Sometimes you have to get the truck on level ground.

It's a headache that we ought not have to put up with, and another reason so many people are staying away from the ESOF, I'm afraid.

If it just won't shift you may have to take it in. If it was me I would still "fiddle" with it until it began to work again, just to make sure. --- but I'm hardheaded.

 

I have tried letting the truck sit in neutral waiting for it to engage, I have tried driving around and turning the 4x4 on and off waiting 3-4 minutes for it to engage, but nothing is happening. I also turned the key on, but did not start the truck and tried the 4x4. I heard some clicking up front, but nothing happened. If a truck is not running, but the key is on, will the 4x4 engage? I have never tried that before.

 

Yes, the servo motor will "rotate" to engage the transfer case without the engine running and the key ON.

You should be able to hear the motor energizing and engaging.

Just curious, you heard a sound "up front"? Could you tell if it was a relay or did it sound more like the "clunk" of the servo?

Just to make sure that your light is not burned out, have you tried to rotate the driveshaft? Or do you know for certain that it's not in 4WD?

 

the sound I heard up front was not a clunk, but about 10 clicks then it stopped. After turning the **** to 4x4 and driving in the snow it is still in 2 wheel drive. When I start the truck up the dash lights come on and the 4x4 light is operational. I just got off the phone with the dealer and he thinks it is the vacuum actuator on the front axle. He said it is a fairly common problem, so I am taking it in on Weds to have the dealer look at it. Thanks for your help

 

He thinks the vac solenoid keeps the 4WD from engaging? That's a new one.

That clicking you hear is the electronics to the servo. It's hunting a hole, so to speak. It could be a relay gone bad, but the actuator, I think would be a whole different can of worms.

Let us know what they find out, will ya'?

 

The service manager said it was about a $70 part and one hour labor to replace whatever he thought was bad. I will let you know what they find. Maybe it is time for a new truck? Hopefully it is nothing major though.

 

Off the record:

I will be willing to bet they replace the servo motor.....

Back on the record.
It is hard to imagine that the vacuum solenoid went bad overnight.

I have been where you are, OAGES, and it is frustrating. Hopefully, someday, a mechanic/engineer/whatever will take it upon themselves to figure out why these things just go bad (or seem to go bad) for no reason at all.

Good luck and please do let us know.

 

I don't see anywhere in this thread where you tried locking the front hubs manually? You have to be moving to get the thing to engage - read my notes below.The clicking is the servo on the transfer case - it will click like that if it can't get into 4x4 especially when you are not moving. Then it gives up, and you're still in 4x2. It might be bad.

A couple of notes on ESOF, not really a direct answer to you, but some rules-of-thumb for ESOF that I have learned from my '01

I have had the hubs not lock when putting it in 4x4. Driving in the rain, I always test it, to keep it moving - doesn't seem to help it much though

When going into 4x4, make sure you are rolling - it says so in the manual. That's why it's "shift-on-the-fly" ... you have to be flying (or crawling)

Here's the poop:

1) Put the **** in 4x4 high
2) Servo on transfer case goes into 4HIGH
3) Vacuum solenoid gives 20 second vacuum pulse to front hubs - they should lock (if they aren't already, see below) Sometimes on straight wet pavement, I have had the hubs NOT lock - because the axles are all turning at the same speeds and the teeth in the hub don't line up (I know, my tires aren't really that alike in diameter, so I don't know why this is).
4) You should be in 4x4 high
5) Stop completely, shift to neutral and put in 4x4LOW, servo on transfer case should go to 4LOW
6) Reverse above to get out. Getting out of 4x4 may take some jockeying - make sure you are OUT before getting on dry pavement. Vacuum solenoid will give 5 second pulse to front hubs, so there's not a lot of time to unlock.

If you didn't know this already, I am going through this for all the other people out there...

NOTE: I have had BOTH front hubs auto-locked when NOT in 4x4. Putting in 4x4 actually seemed to UNLOCK the hubs (it would be in 4x4 for about 1/10 of a second). I get around this by turning off the truck with the **** in 4x4. Then, turning the **** to 4x2 with the truck OFF - then restart. Get moving, put in 4x4, hey it WORKS!

NOTE 2: I have had one or the other hub unlock after the 20 second pulse is over. This is usually because there was no load on the axle/hub to keep it locked in when the vacuum went away (like when you're not moving!) - this might be a stuck hub, but not so sure. It hasn't happened in a long time, and only did it for a few weeks (2.5 years with the truck so far).

NOTE 3: ESOF has worked for me in a situation where I had the right front wheel almost buried in a sink-hole (old trash pit covered over for 50 years). Didn't even get out of the truck - put it in 4x4, then 4x4LOW and backed right out like the hole wasn't even there. AT WORST, I would have had to get out and MANUALLY lock the hubs.

 

Good point, krewat.

Instead of saying:
I should have said: Just to make sure your light isn't working properly, have you tried to rotate the front driveshaft by hand to see if (1) the transfer case is engaged, or (2) to see if the hubs might be locked.

Still, I think that the "system" just went into that dreaded ESOF coma and is reluctant to awake.

Seriously.

 

To figure out what's not working, I did this:

1) Jack up front of truck so both front wheels are off the ground (or do all four if possible)
2) Turn **** to 4x4
3) IMMEDIATELY get out of truck and spin one of the front wheels by hand, then the other.

If you spin one wheel, and the other turns the other way, and the front driveshaft is NOT turning, it's in 4x4. Check after 30 seconds to see if the hubs are STILL locked after vacuum is removed. Try turning the front driveshaft by hand - if it turns, the transfer case is not going into 4x4 - or If you spin one wheel and hold the other (chock it with something) and the front driveshaft turns, the transfer case is not going into 4x4 - bad fuse, servo/sender, wiring or (not as likely) bad transfer case.

If you spin one wheel, and the axle doesn't turn with it, that hub is not locking up. Check both sides to complete the experiment.

Put the **** back to 4x2 and check front hubs and front driveshaft as above after waiting 10 seconds - the axles should not turn (might follow the wheel VERY slowly), and you should be able to turn the front driveshaft by hand without the front wheels moving.

After doing this a few times (yes, check it at least twice), get back to us with the results.